From Norsemen to Normans - Viking and Medieval Dublin.
Like most Irish towns, Dublin was founded by Vikings (Scandinavians), who, after 841AD, settled along an east-west ridge of high ground between the Rivers Liffey and Poddle.
In 1014, along with theirlocal Irish allies, they were defeated at the battle of Clontarf (north of the city) by Brian Boru, king of Munster (southern province of Ireland). In 1170 Dublin was captured by the Anglo-Norman adventurer, Strongbow, who in turn was forced to turn thecity over to his overlord, King Henry II of England. In 1204 his son John built a caste beside the Poddle's Black Pool (Dubh Linn in Irish) which provided a secure seat for England's administration of Ireland over the next 700 years.